Simultaneously scouring and bleaching wool



Patented Sept. 6, 1 949 SIMULTANEOUSLY SCOURING AND BLEACHING WOOL Archie Louis Dubeau, Rumford, R. I., assignor to Mathieson Chemical Corporation, a corporation of Virginia No Drawing. Application April 19, 1946, Serial No. 663,636

3 Claims. (Cl. 8-139) This invention relates to improvements in the processing of wool including both shorn wool and pulled wool.

In accordance with conventional practice, wool before utilization in the production of yarn is subjected to treatment in a series or train of five treating vessels known as bowls. In the first bowl of the train, the wool is desuinted by washing with cold water. In the 2nd and 3rd bowls, the desuinted wool is scoured, usually at a temperature of about 125 F., with an aqueous solution of soap and sodium carbonate. The 4th and 5th bowls are essentially rinsing bowls, but the last bowl, from which the wool is passed to a dryer, may contain a bleaching agent, conventionally hydrogen peroxide.

The scouring in the No. 2 and No. 3 bowls,

grease recovery equipment, proceeds with periodic removal of about half of the solution and replacement of the removed portion with warm water, fresh soda ash and soap being added to maintain the solution at the desired chemical concentration. Soda ash and soap are also continuously or intermittently added during the periods between the half dumps. At the end of 24 hours, the bowls are usually completely emptied, thoroughly washed and charged with fresh liquor.

Where continuous grease recovery equipment is employed, the scouring solution is circulated through the wool and through the grease machine, the solution ordinarily being caused to flow from the No. 3 bowl to the No. 2 bowl, through the grease machine and then back to the No. 3 bowl. Some operators, however, prefer to recover the grease from the No. 2 bowl only, in which case the scouring liquid is withdrawn from the wool exit end of the No. 2 bowl, passed through the grease machine, then returned to the No. 2 bowl at the wool entering end of the bowl. In either case the scouring liquor is periodically fortified by the addition of fresh chemicals.

If during the securing of shorn wool by the conventional method, a sample of the scouring liquor is taken from the first bowl, in which about 90% of the scouring is accomplished, before each addition of soda ash and a double titration with .09 normal HCl run on the samples using phenolphthalein as the indicator in the first titration and methyl orange as the indicator in the second, it will be found that the spread between the phenolphthalein end point and the methyl orange end point (total alkalinity) in terms of cubic centimeters of acid becomes progressively greater. Thismeans that the proportion of carbonate converted to bicarbonate during the operation progressively increases, albeit a part of the total alkalinity may be due to the presence of compounds other than sodium carbonate and sodium bicarbonate.

The accompanying Table 1, submitted in illustration of the immediate foregoing, is based on an operation carried out without the use of mechanical grease recovery equipment in which the wool was treated at the rate of about 1000 pounds per hour. The liquor in the N0. 2 bowl consisted initially of 3500 gallons of water, 120 gallons of soda ash solution containing 92.5 pounds of soda ash, and 30 gallons ofsoap solution containing 8.3 pounds of soap, While the liquor in the No. 3 bowl at the beginning of the operation consisted of 1500 gallons of Water, gallons of soda'ash solution containing 46.25 pounds of soda ash, and 30 gallons of soap solution having a soap concentration of 0.277 pounds per gallon. As the scouring proceeded, the liquor was fortified every 45 minutes by-adding 36 gallons of soda ash solution containing 27.8 pounds of soda ash to the No. 2 bowl and by adding 18 gallons of soda ash solution containing 13.9 pounds of soda ash together with 12 gallons of soap solution containing 3.33 pounds of soap to the No. 3 bowl. At the end of each six hour period, half of the scouring solution was withdrawn from both scouring bowls and the withdrawn solution replaced with water. Following each addition of make-up water, 90 gallons of soda ash solution containing 69.5 pounds of soda ash and 30 gallons of soap solution containing 0.277 pounds of soap per gallon were added to the No. 2 bowl, and 45 gallons of soda ash solution containing 34.6 pounds of soda ash and 30 gallons of soap solution were added to the No. 3 bowl.

TABLE I Total 0. c.s C c. s .09

' .09 normal Alkalinity Apparent Sample ggflgf H01 to Calculated Ratio, Car- No. phthalein Methyl as NazCOx bonate:Bi- End Point Orange End and NaHOOa -carbonate Point The samples in the table were taken immediately before each addition of soda ash and soap. Although the total alkalinity is calculated as due entirely to sodium carbonate and bicarbonate, it is to be understood that a relatively small part of the alkalinity may derive from other compounds formed during the scouring having a pI-I value similar to that of sodium bicarbonate." @llalinit'y carbonate is 5 calculated" by multiplying the cubic centimeters of acid to the phenolphthalein end point by 1.06,; alkalinity as sodium bicarbonate by subtracting twice the cubic centimeters of acidto the 'phenel phthalein end point from the cubic centimeters :n-

of acid to the methyl orange endpgi tia d multi plying the difierence by The tab1e,.s,hQw that in the conventional process, in which no effort is made to control the carbonate; bi;

carbonate ratio, the weight 'of""b1'carbn 6 I 'the liquor The added alkali, it will be underpresent in the solution soon exceeds twictfi' weight of carbonate present.

In accordance with the present invention I clude; sodium h o ite. as: a cemmnent; f. t e 99 i uor, audr isor z 1t he,coinnosi-v 2o qutq h eiauon at h at o r ha sura 012:. amed; ro mu tin -yina he. ubic; centimeters. of .09 normal HCl required to reach the, phenoll thaiein ncllneint. hy. .-Qfi; o., he fi ure obtained xl lultihlyina ififi finee. between; twice he bic e .DQ- normal Hclitoinhenolr and he. cubic. centimeters. fiilllimds to reach. the methyl W Q A L'DQH I. xQ-Bziis, K pt: substantially at. all imfisw thinn ha ange;Qhabout 1; 0.5 tp.1: 30 W the ham usi ifiherchlotite, bleachingas, tel st-seamin qiz h iwool a hi It; will be; understoodL that reference. in the.

d. tq ,thelwei llt; ratio. of; apparent. t b carbonate isjntended tomean the 35 deter m ned bytheproceduregjustedescribed.

Th uehthe, eachinelohwool'; with hydrogen p rg de .solutgionsr fisbeenpracticedextensively.v sr d' at dr hetforepart; hereof, hydrogen the wogl. h a;rsh 'Highmvconcentrated solutions re eea nown to. ma ernit damage thewooli ttire QWer-.. s ,n;ce trations the bleachin a t dr@s@n .apere i ei s gobj ctionablyis o lfi Qild he; present invention. whereby ar a W Q nroc ssedi; by the conventional 50 et with at PQIFQXide.

ob ainedjiexcellent; results. using; the

b0nti %.=by .weight,oi available. chlor ne, t ll, higher; Concentrations of the chlorite may be used withoutidangerbr damag ing the wool, but withoutmaterially improved results. Generally satisfactory results are ob; tain'e'd'by t e'use'of the chlorite in concentraattempt to use a chlorite in the bleaching of wool has heretofore been discouraged by the fact that the desired characteristics of wool are destroyed or are at least adversely afiected by, treatment with chlgorine or with chlprine compounds, such asthe hypochlo'rit's which in use evolve chlorine.

In the scouring of shorn or other acidic Wools, the composition of the scouring liquor can be i"r 1ed-"wi-thin the prescribed limits on alkalinity, with advantage, through the contmuousxor intermittent introduction of controlled amdunts. of; aqueous; caustic soda. Less preferably, aqueous daustic potash or an aqueous solutionof, a l allg al i ne earth metal hydroxide, such as; calcium hydroxide may be introduced into stood; acts to convert egicess bicarbonate back to carbonate in accordance with the equation:

The alkaline solution is not, of course, addedfron'r the 'very beg-inning of the securingwhen theconc'entrationof bicarbonate-is negligible, in fact it i's advantageous in preparing theini-tial solutiontoadd bicarbonate.-

In thev case of'=pul-led "-w oolwhere sodium bi carbonate' is -net formed-as an incident ofthe scouring the wool being alkaline from pre treatment with-lime; the desired composition of; the-scouring I liguor is; maintained in accordance with lily-invention by the continuous or inter mittent addi-tion of-sodiiim bicarbonate oran acid'or-aci'd salt, such-as acidphosphate; The initial solution in the in-st'ance ofalkaline woelsshouldbe madeup to contain bicarbonatein an amount indicated by the l'i-initsabove;

a preferredembodiment of my inventionas-appl i ed te acid wool,- the caustic solution is company offli'quor'rmoved fromthe'bqwl rather than 'directlytc thefbowl Thecaustic may becofn'e ee is1et 1y-reat'ee before it-enters the bowl. Direet addi tion offthe caustic solution to the bowl appears" disadvantageous as resulting -i' s i 'd? l 'hn is fihe W09 i The 9 19 1 to which the caustic-solutionis to be added is mi i bl i i i rawe rom h W 9 tn n h'f a l asse I h re l h I a r u h r. nk. w'jer ef the caustic: solution charged to, the 'qt t and, he. a$ i $Q i9 t Q 1 WP L Q nfix, the gol-enterih ggend oi the bo wl. The caustic, solution most K suitably I has a NaQI-I concentrae- ,i lissaar; iie im iio s' e PlW a-Wtih dv nt e rite at whmh ,the, caustic solution is added is i h neiarai r i r ati nwhi e es: trat'e'd by the following examples:

WWP Q 1 Z 7 hawjool treatedsis; shorn.. .w.ool.: The run is i arted; immediately, after; thenbowls .had been il rfimp iedand th remmledscouring liquor replaeed-Jvvithhwater; Upon titration-u of :10- c. c. samples,-. following addition. ofumalie up ehemi alstein'cluding, chlorite, witha .09 normal 1 H015 2.7 cc; 0;; of acid is required to reach the phenolphthalein, en'di:pointQandLT-l :0 c. of acid is re- 1 1111861 zto reach1the methyl orange end point.

Theuwool is;fed .to.the..system at the rate of abQut; 1 2Q0:.-apounds: per'lhour.

The caustic so1u- Apparent Ratio, CarbonatezBicarbonate 81%137367658 L LLLLLLLLL .hkhlllllllll Apparent Ratio CarbonatezBicar- Donate 7 562 5 %%%%M001445366 L LLLLLLLLL h11111111111111 At the pH at which the substantially throughout the My process as compared with the conventional and labor costs. Because the wool can be charged ing of the liquor is required, greatly increased ment. In manyinstances, the process can be Alkalinity Calculated aSNazCOz and NaHCOs 44566 ww ummwmnD-baun n say from 300 pounds of wool per hour to 600-700 pounds per hour and with noticeable improvement in the quality of the processed wool.

The bleaching action of the chlorite in my process appears to be enhanced by its environment and conversely the presence of the chlorite in the liquor seems to increase the scouring ability of the liquor.

little, if any, chlorine dioxide is evolved which is distinctly advantageous because of the corrosive properties of this gas.

I claim:

1. A continuous process for simultaneously scouring and bleaching wool which comprises continuously passing the wool to be treated in contact with an aqueous liquor containing soda ash, sodium bicarbonate, soap and sodium chlorite and maintaining the composition of the liquor such that the Weight ratio of apparent carbonate to bicarbonate is Within the range of method is definitely cheaper in both chemical at a constant high rate and because less changproduction can be achieved with same equip- Ohlorite Concentration (based on weight of available chlorine) Chlorite Concent-ration (based on Weight of available chlorine) operated to increase production more than 100%,

2. The process of claim 1 wherein the chlorite concentration of the liquor is maintained within the range of 0.01% to 2%, based on the weight of available chlorine.

180 55 liquor is maintained according to the invention,

The solution TABLE II mal HC 1 to TABLE III C. c.s .09 normal H01 to end point Methyl Orange O. c.s .09 nor- 0. c.s .09 normal HC 1 to end point Phenolphthalein 0. c.s .09 normal H01 to end point Phenolphthalein Emample 2 TABLE IV Sample No.

Sample No.

Time

tion used consists of about 20 pounds sodium hydroxide in 50 gallons of water.

is continuously added to liquor from the first scouring bowl only, and at a rate equivalent to 3.5 pounds of NaOH per thousand pounds of wool. Data on typical runs are given in accompanying Tables 2 and 3:

mmmmwmmmmmwm Time wmwmmwmmwmmmmmm addLLzarLaaaaae 111111 Pulled wool is treated at the rate of 700 pounds per hour using conventional bowls. The

130 F. and the make-up on the scouring bowls 50 is as follows:

tional of sodium bicarbonate is added to the first scouring bowl in increments of about 16 pounds. Data on such a run is given in the following table treatment is carried out at a temperature of Water gallons 3,750 Sodium bicarbonate pounds Sodium carbonate do Soap do Sodium chlorite do During the course of the run, 100 pounds addim w 0 a 5. a 0 D 1 o 0 7 a 0 0 om 46619 uuN 711575 a: LL Rm nnnnni 0 m N m C 5flfififi ra 9 PN t 3 m0 42646 357777 ra an m aaaanw mm 000000 0 E 157888 P OMQMOmOmQWOm m mmmnmw n a4 6 7 e1 1 3. The process of claim 1 wherein the chlorite 1 Based on weight of available chlorine.

24813201? I 1 V onitentpof the: liq'lior is? maintaimadiwithim the UNITED STATES PATENTS fangetoif 0;02'% to 0.03% baseckomthewightaofi available'ch'lorine' Number Name Date v l. v 'r I M 54,727 Poulson' Ja 29;, 191-8 ARCH-IE LOUISJDUBEAU, ,1 2. Mackenzie Dec I2 1939 REFERENCES CITED FOREIGN PATENTS The folldw-ing references are of record in the Number Country Dht file of this patent: 549,678 Great Britain Dec. 2, 1942 

